How important is an audio rack?

Another important consideration in an audio rack, IMO, is that it is open on all sides, so there is plenty of air, and your components do not overheat. I use the Sanus Natural Foundations rack, which has glass shelves. They are very sturdy, and I have no vibration problems.

"an extreme audiophile I visited had sturdy metal racks; the kind you see in Stereophile. Since his sound was the best I've heard, I know they make a difference."

Maybe, but I'd wager the rest of the gear and the setup as a whole had a lot to do with it.

I guess one would have to switch racks and a/b compare to know for sure.

I bought a used Billy Bags rack just cuz I liked the way it looks. It was an upgrade and logic dictated there'd be an improvement in sound quality but I honestly wasn't expecting much. I was very surprised at how much better the system sounded after installation. NOT one of those subtle I-think-I-hear-a-difference-type audiophool tweaks either, it was a clear as day improvement!

My stuff sits on wooden shelves, but an extreme audiophile I visited had sturdy metal racks; the kind you see in Stereophile. Since his sound was the best I've heard, I know they make a difference. I believe the question "How much"? is related to the depth of one's pockets.

It is very important. The best in my opinion is SYMPOSIUM ISIS it is Aircraft Aluminum which is neutral.Wood is wood which is not neutral.This rack will keep vibrations from getting to your componants.

Hi Dayglow,
Everything affects everything else and interacts with everything else. That being said a rack can make a nice improvement. Possibly equal to a cable or power cord.
Lent my son a Zoethecus rack for a bit and he was amazed at the improvement. Didn't think a rack could make a difference but he heard it so...
I like maple for blending in but other woods do as well. Most musical instruments are wood or were at one time so that seems like a reasonable idea to stick to wood.
Though I have seen some really nice metal racks but have not heard them with a system so I could be swayed.
Bette me than the rack.

Aesthetically, perhaps important to some.

Regarding sound quality, its important that it be built solidly enough to serve as a rigid foundation. I tend to like low profile racks or shelves for this reason. Cheaper and most effective. Tall, vertical units are more problematic and cost more to do right. Equipment that sits higher up off the floor will tend to be subject to vibrations of greater magnitude, like a high rise in an earthquake.

I also tend to prefer wood construction in that the damping characteristics of wood is generally quite good compared to other materials, say metal or glass.

That's about it.

Its also imporant that the floor it sits on functions well as a rigid foundation. Concrete foundations work very well. Upper levels of homes, especially newer ones, are more problematic.

How much all this matters of course depends on the quality of the system and the needs of the listener. Many will not give a hoot in practice. In my main rig, I care. In my second 2 channel A/V system, I do not care. WAF matters more. That second system still sounds fine.
Can't match my main rig though in critical listening comparisons.